LONG BEACH - When the California Department of Education released results from state standardized tests last month, dozens of Long Beach schools celebrated significant gains.

But as the Long Beach Unified School District showed overall improvement, scores plummeted in many of Long Beach's traditionally top-performing elementary schools.

Of the district's 58 elementary and K-8 schools, nearly two dozen saw double-digit declines on the state's 2012 Academic Performance Index, leaving district officials concerned that budget cuts may be having a greater-than- expected impact in the classroom.

Designed to measure a school's performance and improvement, the annual API is based on a collection of standardized tests. Schools and districts are each given a score ranging from 200 to 1,000, with 800 being the long-term performance goal.

Schools are expected to increase their API by a certain number of points each year, including among various demographic groups. While experts say it's typical for schools to fluctuate a few points, some local elementary schools are experiencing never-before-seen changes, said Jill Baker, Long Beach Unified's assistant superintendent for elementary and K-8 schools.

Roosevelt Elementary saw a 26-point loss, while Harte Elementary lost 41 points. McKinley, Edison and Burnett elementary schools all lost more than 30 points. Lafayette Elementary had the largest decline in the district, with a 63-point drop. The schools are all traditionally high-performing, with API scores close to or well above the state target of 800.

While the school district is still determining the cause for some of these declines, Baker said budget cuts have certainly affected classrooms.

"Our district has experienced some really significant changes and we've been very mindful of protecting individual classrooms, but some things have begun to impact classrooms," Baker said.

"Last year we saw larger classes, fewer counselors, fewer tutors, fewer nurses, less support for teachers and fewer librarians," she said. "All of these different variables have had an impact, but we still don't know exactly to what degree."

The state's third-largest school district has laid off more than 1,000 employees and cut its budget by $300 million in the past four years in an effort to remain fiscally stable in a time of severe state funding cuts. The district will lose an additional $35 million in annual funding if Proposition 30, Gov. Jerry Brown's tax measure, fails in today's election.

Baker noted that the district still managed to grow its overall API by 10 points to 781 this year, despite the millions of dollars in cuts.

At the same time, nearly all of Long Beach's middle schools showed significant gains, thanks in part to a new focus on self-contained sixth-grade classrooms and higher enrollment in eighth-grade algebra.

Baker said the increased class sizes in the elementary grades last year may be partially to blame for the steep declines in performance in some elementary schools. However, some schools still showed significant gains despite large classrooms, she added.

The school district in the 2010-11 year bumped the student-to-teacher ratio to 30 to 1 for kindergarten through the third grade and 35 to 1 for fourth and fifth grades.

Baker said many classrooms previously had about 20 students.

"Moving from 20 to 30 students in a classroom can be a tremendous change for a teacher in how they divide up their time," she said.

The 63-point API drop to a score of 796 this year was a huge disappointment for many parents at Lafayette, a nationally recognized school that serves mostly underprivileged children in Central Long Beach.

In 2011, parents were outraged when nearly half of Lafayette's teachers were laid off under teacher seniority rules. Parents at the time were concerned that the cuts would disrupt the school's foundation of learning.

Parent Ricardo Linarez ran for a seat on the school board earlier this year with the hope of facilitating change in the district.

"Parents have worked so hard with the school to help raise the API scores and to see this loss is very sad," said Linarez, whose daughter is a second-grader at Lafayette.

Linarez said the school has a strong base of parent volunteers who are dedicated to raising funds and helping the school boost its API. Last year, parents raised more than $5,000 to buy 30 computer printers for classrooms, he added.

"It's not just about the layoffs, our classrooms need resources," he said.

Baker said resources are becoming ever more scarce under the weight of budget cuts.

"We're seeing the impact of millions of dollars in cuts and that's why we need our community's support in providing resources for our schools," she said. "We're all trying to do more with less resources."

As for parents' concern about their school's API, Baker said API should be analyzed over a period of time as opposed to looking at year-to-year fluctuations.

"We've had significant drops and within a year or two they are back to where they stated," she said. "The API is not the only measure of a school's performance, so I would urge parents to keep supporting their school and be active in their child's education."

While the district is short on resources, Baker said schools this year are evaluating student progress and working on teacher development to boost performance on next year's API.

Webster Elementary, nestled on the city's Westside, is the only elementary school in the district that has maintained its 20-to-1 student ratio, thanks to a special school improvement grant for select public schools. The school, which has received the grant since 2006, has to meet certain criteria and faces regular assessments to continue to receive the grant, said Principal Maria Martinez.

In a second-grade classroom on Friday, teacher Susan Ballmer worked with a group of 19 students on a lesson in government. Ballmer said the smaller classroom size is helpful.

"I feel like I can meet with every child every day and address their needs," she said.

Martinez said the school has benefited from smaller classes, but regular assessments, grade-to-grade collaboration and a strong parent support group are the real factors in the school's success. This year, Webster celebrated a 32-point API gain for a score of 834.

"We've definitely been lucky with the smaller classrooms, but we've also worked really hard for our improvement," she said. "Classroom size is an important issue, but it's what goes on in the classroom that really counts."